"Exception: An eligible receiver is considered to be an obstructing opponent ONLY to a point five yards beyond the line of scrimmage unless the player who receives the snap clearly demonstrates no further intention to pass the ball. Within this five-yard zone, a defensive player may chuck an eligible player in front of him. A defensive player is allowed to maintain continuous and unbroken contact within the five-yard zone until a point when the receiver is even with the defender."

Seems to suggest five yards is considered from the line of scrimmage regardless of where it is. This isn't clear either and only applies to the defender.

But seems it would be a clear case of "picking" the defender if you don't call it blocking, which is illegal anywhere on the field.